void main() {
  Map<String, dynamic> map = {'name': '张三', 'age': 18, 'sex': '男'};

  print(map);
  print(map['name']);
  map['name'] = '李四';
  print(map);
  map['hobby'] = '打游戏';
  print(map);

  map.remove('sex');
  print(map);

  map.forEach((key, value) {
    print('$key---- $value');
  });
}
